CHICAGO (AP) - After tracking down a small alligator skulking in a baggage claim area at Chicago's O'Hare International Airport, authorities are now hunting for its traveling companion.

The Chicago Transit Authority has released a series of images showing a woman who they believe rode to the airport on a CTA Blue Line train with the 2-foot-long gator in the early morning hours of Nov. 1.

Thanks to one of the most extensive surveillance systems in the United States, officials know this about the alligator's trip to O'Hare: It boarded a train at the Pulaski stop - with the woman - at 1:17 a.m. The security camera captured the woman petting her little friend on her knee as she talked on her cellphone.

Blue Line rider Mark Strotman also snapped a picture of the woman and the alligator with his phone.

"Everyone who got on sort of did a double take, followed by a few expletives because they couldn't believe there was an alligator on the El," Strotman told WMAQ-TV.

"She couldn't have been nicer," Strotman said. "She said she had had it since it was very little. She was petting it, and she was very friendly with it. It didn't seem like she was trying to get rid of it."

An hour later, the woman, presumably with the alligator, disembarked the train at the airport. Then, at 2:44 a.m., she is again recorded by the security cameras near the O'Hare stop, but with no reptilian companion.

An airport employee found the alligator later in the day under an escalator near baggage claim No. 3 (Insert alligator bag joke here). Police captured the reptile by trapping it beneath a trash can.

Not only did officials give the alligator a name - Allie - but it was handed over to people who could care for it, just in the nick of time.

"It's not responding well to food... It hasn't had the proper nutrition. Its growth has been stunted. It has a bent spine, soft bones, soft fingernails and a soft skull," Jason Hood, president of the Chicago Herpetological Society, told The Associated Press. The society took custody of the alligator.

Hood said the alligator spotted on the train has the same markings as the animal captured at the airport. It was never a serious threat to the public, too small for its bite to hurt anyone, he said. It's believed to be a 2- or 3-year-old American alligator and its gender is unknown.

Hood says the only way to determine the sex of an alligator is by an internal exam and, he notes, "you want it not to be on death's door before you bother about that."

As for the woman, she could be in trouble because while carrying an alligator bag may be considered stylish, carrying a live alligator is a crime. Hood said the Illinois Dangerous Animals Act makes it illegal to own an alligator in the state.

What's more, the CTA said she could be in yet more trouble.

"Those responsible for this act can face a misdemeanor charge of cruel treatment of an animal or face a fine of $300 to $1,000 for cruelty to animals for abandoning the animal in a public place," the authority said in a news release.

CTA spokeswoman Lambrini Lukidis said releasing the photos provides a good reminder that 3,600 cameras are keeping a close eye on the transit system.

"If a more serious crime is happening in our system," she said, "there are ways for us to work with investigators and the police department."

The decision to release the photos also reflects the public interest in a very unusual sighting, Lukidis said. "We've had deer on train platforms and roosters on buses and trains, but this is the first reptile, at least that I'm aware of."